Tripod-head for surveyors



Y W. J. YOUNG.

Surveyors Tripod.

No. 20,915. V Patented JUly13y1858.

N4 PEYERS. PMI o-l-hbognphw. Wnhinllm D. C.

UNITED STATES PATENT OFFICE.

W. J. YOUNG, OF PHILADELPHIA, PENNSYLVANIA.

TRIPOD-HEAD FOR. SUBVEYORS.

Specification of Letters Patent No. 20,915, dated July 13, 1858'.

To all whom it may concern:

Be it known that 1, WILLIAM J. YOUNG,

of the city of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Surveyors Tripods; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing and to the letters of reference marked thereon.

My invention relates to an improvement in the heads of tripods used by surveyors in connection with theodolites and other instruments; and my improvement consists in so constructing, the said heads, that the upper portion of the same, to which the instrument and plumb-line are attached, shall be separate from, and adjustable horizontally, to the lower portion, to which the legs are jointed, the usual leveling screws being used as a means of binding the above mentioned portions of the head together after adjustment.

The object of my invention is to dispense with the usual tedious process of moving and depressing one or other of the legs, in order to bring the plumb-line to the desired position. i

In order to enable others skilled in the art to make and use my invention, I will now proceed to describe its construction and operation.

On reference to the drawing, which forms a part of this specification, Figure l, is a general view, drawn to a reduced scale, of a tripod with my improved head. Fig. 2, an inverted plan View of the head, drawn to the full size. Fig. 3, a sectional elevation of the head on the line 1, 2. Fig. 2.)

Similar letters refer to similar parts throughout the several views.

The lower portion of the cap consists of an annular plate (A), from which project the fianches (a). These combined form the three recesses for the upper ends of the legs (6), which are hung to the pins (0), the latter being attached to two opposite flanches (a).

The upper port-ion of the head consists of the circular plate (D), to the center of which is secured the pin (E) for receiving the theodolite or other instrument. To the pin on the underside of the plate (D) is screwed the end of the stem (e), which projects from and forms a part of the hemisphere (C), the latter fitting into the concave socket (f) on the plate (B), this socket projecting through the central opening in the annular plate (A) of the lower portion of the head. On reference to Fig. 2, it will be seen that-the plate (B) consists of three plain projections, each of which bears against the underside of the annular plate (A) in one of the recesses formed by two of the flanches (a). Four nuts (h) are secured to the plate (D), and into these nuts screw the ends of the leveling screws (2'), the lower ends of which bear on the surface of the plate (A), the screws being furnished with the usual disks with milled edges, so as to be easily turned by the finger and thumb of the operator. The plumb-line is attached to a pin (j), which projects from the underside of the hemisphere As far as regards the upper plate (D) with its pin (E), the hemispherical coupling, and leveling screws (2'), the arrangement is similar, both as regards construction and operation, to that of tripod-heads in common use. The socket (f), however, has hitherto either formed a permanent portion of that part of the head attached directly to the legs, or a portion of a plate rendered adjustable horizontally by means of screws independent of those used for leveling purposes.

If arranged on the former plan, the operator must resort to the usual tedious process of repeatedly moving in or out one of the legs (6) or depressing the same, before he can bring the plumb-line to coincide with a given point in the ground. Should the latter be of a stony nature, the difficulty and delay attending the adjustment would be increased. The method of adjusting the upper portion of the head by means of horizontal slides and screws, a plan sometimes resorted to, requires a manipulation almost as tedious as that above mentioned.

In my improved head, the opening in the plate (A) is larger in diameter than the socket (f), which projects through the opening, and each of the three projections, which form the plate (B), is narrower than the recesses formed by the fianches (a). Consequently, when the leveling screws are turned to an extent sufficient to relieve their lower ends from contact with the plate (A), the plate (D) with its pin (E), the instrument attached to the latter, the leveling screws the hemisphere (C), its plumbline and the plate (B), all of which appertain to the upper portion of the head, may be moved horizontally on the lower portion in any direction, to a limited extent. After being adjusted to the desired position, the screws (2") may be turned until their lower ends bear on the surface of the plate (A), and force the hemisphere (C) tight within its socket (f), when the two portions of the head become firmly bound together.

It will now be seen without further description, that my improved tripod-head affords every facility for a rapid and exact adjustment of the instrument to the desired position by the hand of the surveyor, after the tripod has been placed in proximity to the point in the ground, wit-h which the plumb-line must coincide. It will also be seen that the pins serve the double purpose of leveling the instrument and of securing the same in the position, to which it may have been adjusted horizontally, thus enabling the operator to perform two duties without changing his position, and without the usual handling of different portions of the tripod.

Without confining myself to the recise form and arrangement of the within described parts, I claim and desire to secure by Letters Patent Constructing the head of a surveyors tripod in such a manner, that the portion, to which the instrument and plumb-line are attached may be adjustable in any direction horizontally to the portion to which the legs are jointed, when the usual leveling screws serve the purpose of binding the two portions of the head together after adjustment, as herein set forth and for the purpose specified.

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

WM. J. YOUNG. WVitnesses HENRY HowsoN, JNo. WV. ODIORNE. 

